hdu 2830 Matrix Swapping II

#include<iostream>#include<cstring>#include<algorithm>#include<cstdio>#include<vector>#include<sstream>#include<string>#include<climits>#include<stack>#include<set>#include<bitset>#include<cmath>#include<deque>#include<map>#include<queue>#define iinf 0x7f7f7f7f#define linf 1000000000000000000LL#define dinf 1e200#define eps 1e-11#define all(v) (v).begin(),(v).end()#define sz(x)  x.size()#define pb push_back#define mp make_pair#define lng long long#define sqr(a) ((a)*(a))#define pii pair<int,int>#define pll pair<lng,lng>#define pss pair<string,string>#define pdd pair<double,double>#define X first#define Y second#define pi 3.14159265359#define ff(i,xi,n) for(int i=xi;i<=(int)(n);++i)#define ffd(i,xi,n) for(int i=xi;i>=(int)(n);--i)#define ffl(i,r) for(int i=head[r];i!=-1;i=edge[i].next)#define ffe(i,r) for(_edge *i=head[r];i;i=i->next)#define cc(i,j) memset(i,j,sizeof(i))#define two(x)          ((lng)1<<(x))#define lson l , mid , rt << 1#define rson mid + 1 , r , rt << 1 | 1#define mod  1000000007#define pmod(x,y) (x%y+y)%yusing namespace std;typedef vector<int>  vi;typedef vector<string>  vs;template<class T> inline void checkmax(T &x,T y){    if(x<y) x=y;}template<class T> inline void checkmin(T &x,T y){    if(x>y) x=y;}template<class T> inline T Min(T x,T y){    return (x>y?y:x);}template<class T> inline T Max(T x,T y){    return (x<y?y:x);}template<class T> T Abs(T a){    return a>0?a:(-a);}template<class T> inline T lowbit(T n){    return (n^(n-1))&n;}template<class T> inline int countbit(T n){    return (n==0)?0:(1+countbit(n&(n-1)));}lng Pow(lng x,lng y){    if(!y) return 1;    lng res=Pow(x*x%mod,y/2);    if(y&1) res=res*x%mod;    return res;}bool a[1111][1111];int n,m;int h[1111],te[1111];int ans;char c;int main(){    while(scanf("%d%d",&n,&m)==2)    {        ff(i,1,n) {getchar();ff(j,1,m) {c=getchar();a[i][j]=(c=='1');}}         cc(h,0);         ans=0;         ff(i,1,n)         {             ff(j,1,m)             {                 if(a[i][j]) h[j]+=1;                 else h[j]=0;                 te[j]=h[j];             }             sort(te+1,te+1+m);             ff(j,1,m)             checkmax(ans,te[j]*(m-j+1));         }         printf("%d\n",ans);    }    return 0;}